It’s about companies that discover that their Web sites are successful in markets that they never expected — such as Friendster in the Philippines or Orkut in Brazil.

Google’s social-networking site, Orkut.com, meanwhile, has been a surprise hit in Brazil. Today, 66 percent of Orkut users are Brazilian. Rounding out the top three are the United States, where 10 percent of users reside, and Iran, home to 7 percent of Orkut members.

For these types of networking sites, the ability to sell advertising is key — and yet smaller markets mean fewer eyeballs which means less money. David Moore, the chief executive of advertising firm 24/7 Real Media, said that there are nine markets other than the US where sites can profitabliy sell advertising.

But I believe that’s all changing. While there are indeed diminishing returns involved, one need only look at Google’s ever-expanding Adwords program to see that no market, no matter how small, is worth overlooking for long. Google now offers Adwords for more than 30 markets — and I wouldn’t be suprised to see that doubled over the next two years. At some point we’re talking nickels and dimes in revenues, but they all add up.

Which makes me think of Chris Anderson and his forthcoming Long Tail book. He talks about the “long tail” of Amazon’s product assortment and how the depth of goods is key to the company’s success. I can’t help thinking that there is a similar long tail involved in Web globalization. Keep your eyes on Google, because it is going to be testing that theory and, because it’s a public company, we’ll get quarterly updates on its financial progress.